The Coast Guard will continue searching the sea floor near the Titanic shipwreck for more clues about what happened to the Titan submersible deep in the North Atlantic waters.

Officials say there isn't a timeframe for when they will call off the massive international search. Efforts to recover the submersible and the remains of the five men who died in a catastrophic implosion aboard the vessel remain ongoing.

Much of the search is being done by remotely operated underwater vehicles known as ROVs that can scan the sea floor.

“This is an incredibly unforgiving environment down there on the seafloor,” Rear Adm. John Mauger of the First Coast Guard District said Thursday. development company MITRE.

The U.S. needs more underwater robots and remotely operated underwater vehicles, known as ROVs, to ensure safety, he said, especially as private exploration of the ocean expands.

“The issue is we don’t have a lot of capability or systems that can go to the depth this vessel was going to,” Rotker said.